PHP Manual: Delay execution

Description

int sleep(int $seconds)

Delays the program execution for the given number of seconds.

Note:
In order to delay program execution for a fraction of a second, use usleep as the sleep function expects an int. For example, sleep(0.25) will pause program execution for 0 seconds.

Parameters

seconds: Halt time in seconds (must be greater than or equal to 0).

Return Values

Returns zero on success.

If the call was interrupted by a signal, sleep returns a non-zero value. On Windows, this value will always be 192 (the value of the WAIT_IO_COMPLETION constant within the Windows API). On other platforms, the return value will be the number of seconds left to sleep.

Errors/Exceptions

If the specified number of seconds is negative, this function will throw a ValueError.

Changelog

Version	Description
8.0.0	The function throws a ValueError on negative `seconds`; previously, an `E_WARNING` was raised instead, and the function returned `false`.

Examples

Example #1 sleep example

<?php

// current time
echo date('h:i:s') . "\n";

// sleep for 10 seconds
sleep(10);

// wake up !
echo date('h:i:s') . "\n";

?>

This example will output (after 10 seconds)

05:31:23
05:31:33

sleep